Tilly
Remember, the DWP is an equal partner with you for the appeal, they can say what they want the Tribunal panel, which usually has a far more open mind to the evidence presented by the claimant to decide what merit it has.
Personally, I would avoid getting into a slinging match with the DWP during the submission stage you won't really be adding anything to what you have already said.
Gordon
Nothing on this board constitutes legal advice - always consult a professional about specific problems